1. Field of the Invention
The invention relates to an integrated logic circuit having a signal input formed by a control electrode of a transistor and plural signal outputs each coupled through a diode to a first main electrode of the transistor, the signal input being connected to means for supplying current, which integrated logic circuit comprises a semiconductor body having a major surface located on an active side of the semiconductor body, a group of regions of a first conductivity type being present on this active side of the semiconductor body, which regions extend on a substrate region of a second conductivity type common to these regions, each of the regions of the first conductivity type being surrounded by an isolation zone which extends from the major surface into the semiconductor body and by means of which at least a number of these regions are isolated from each other at least during operation of the integrated logic circuit, in which a first region of the first conductivity type belonging to the group of regions forms part of the first main electrode of the transistor and the control electrode of the transistor has a surface zone of the second conductivity type which is situated inside the isolation zone surrounding this first region, a second main electrode of the transistor adjoining the major surface and being separated from the control electrode by a rectifying junction, while at the major surface there is provided a system of signal connections which comprises conductor tracks which are separated from the semiconductor body by an insulating layer, a plurality of these conductor tracks each connecting the first region of the first conductivity type through a diode junction to a further part of the integrated logic circuit, the diode junctions constituting the diodes which are each connected in forward direction in series with the main current path of the transistor, the means for supplying current comprising a supply line for connecting a supply source and means for supplying current from this supply line to the signal input, while a conductive connection at least comprising a load element is arranged between the supply line and the first main electrode of the transistor.
2. Description of the Prior Art
Such an integrated circuit is known from I.E.E.E., Journal of Solid State Circuits, Vol. SC-17, No. 4, Aug. '82, pages 687-695, in particular FIG. 9.
In general, the invention relates to logic circuits of, for example, the I.sup.2 L type (Integrated Injection Logic), the ISL type (Integrated Schottky Logic) and the STL type (Schottky Transistor Logic), in which current supply means are present at the logic input and an internal pull-up connection is present between the first main electrode and the supply line or rail. The transistor may be, for example, a bipolar transistor or a static induction transistor and has a main current path located between a first and a second main electrode and a control electrode for controlling the current flowing through the main current path during operation. In a bipolar transistor, the collector and the emitter constitute the two main electrodes and the base is the control electrode.
The internal pull-up connection may simply comprise a resistor or may be composed, for example, of the series arrangement of a resistor and a diode. It is achieved by means of this connection that the delay time of the logic gate circuit succeeding the gate circuits provided with a pull-up connection is less dependent upon the member of preceding gate circuits connected to the input of this succeeding gate circuit. Furthermore, an improvement of the noise margin is thus obtained. In integrated circuits having a large number of gate circuits, all gate circuits may be provided with an internal pull-up connection. These improvements can be realized practically without increase of the energy dissipation by now distributing the current, which without a pull-up connection was supplied solely to the input, over the input and the pull-up connection so that the overall current per gate circuit remains substantially unchanged.
It will mostly be sufficient when only in the case of gate circuits which form part of a critical signal path and whose input is connected to a comparatively large number of preceding gate circuits, these preceding gate circuits are provided with an internal pull-up connection.